Memoirs for a natural history of animals. Containing the anatomical descriptions of several creatures dissected by the Royal Academy of Sciences at Paris / Englished by Alexander Pitfeild [!] ... To which is added an account of the measure of a degree of a great circle of the earth, published by the same Academy, and Englished by Richard Waller.
- French Academy of Sciences
- Date:
- 1688
Licence: Public Domain Mark
Credit: Memoirs for a natural history of animals. Containing the anatomical descriptions of several creatures dissected by the Royal Academy of Sciences at Paris / Englished by Alexander Pitfeild [!] ... To which is added an account of the measure of a degree of a great circle of the earth, published by the same Academy, and Englished by Richard Waller. Source: Wellcome Collection.
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![SSE SIO 6 The Meafure of the Earth, not always found fo precife, and that it feemed that ir ought to have been regularly adittle fhortned in Winter and lengthened in Summer. But that however was but the rorh part of a Line) fo that having a refpect to this variation, it has been judged beft to take the mean between them, and to take the length of 36 Inches 8: ines for the certain Meafure. | if the length of the Pendulum for feconds be once found expreft according to. the ufual Meafure of every place, by this means may be had the proportion of the different Meafures fo exact as if the | originals had been compared, and this advantage would thence | accrue , that for the future any change therein might be difco- : vered. But befides the particular Meafures, an agreement might be found of fuch as follow, which will need no other original but the Heavens. | The length of a Pendulum of a fecond of the middle time might | be called by the name of an Aftronomical Ray,. the third of which fhall be the univerfal Foot. The double of the 4ftronomical Ray makes the univerfal Toife, which will be to that of Paris as 83x to 864. ee times the Aftronomical Ray may make the univerfal. Perch equal to the length of a Pendule of two feconds. | Finally the univerfal Mile may contain 1000 Perches, Hi _ Thefe. univerfal. Meafures. fuppofe that the difference of places ait caufeth no fenfible. variation to the Pendulums. .’Tis true, there | | have been made fome experiments at London, Lyons and Bolognia in | nul Ttaly, by which it feems ong might conclude that the Pendulums | ought to be dhorter in fome proportion as the Æquinoctial:is ap- | proacht. Conformable to a conjecture which has been formerly pro- poled in the Aflembly, that fuppofing the motion of the Earth; | weights ought to defcend with: lefs power under the Aiquinoctial | 1 than under the Poles. But we are not fufficiently informed of the | VE) juftnefs of thefe Experiments to make:any conclufion thence.’ And | ee i] we muft befides note, that at the lague, where the heighth of the ua Pole is greater than at Loydon ; the length of a Pendulum exactly | ul determined by means of Clocks, was found the fame as at Paris. | any ‘Tis for this we advife, thofe who would make experiment with a | qu fingle Pendulum, to make ufe of great Pendulum Clocks, for that | dE LUN otherwife they. will difficultly meet with the juft Meafure. fit | fhould be found by experience. that the Pendulum will be. of diffe- rent lengths in different places, the fuppofition we have made con- cerning the .univerfal Meafure drawn from the Pendulums, cannot hold, but this hinders not but that in every place there will be a perpetual and invariable Méafure. c . The Jength of a Parifan Toyfe, andithat of a Pendulum of fe- | conds, fuch_as:we have now. eftablifht, will-be carefully-prefervedin the Magnificent. Obfervatory,.. which His Majefty has-caufed to be built for the advagcement. of Aftronomy. ; AR-](https://iiif.wellcomecollection.org/image/b30325146_0376.jp2/full/800%2C/0/default.jpg)
